what not to wear

Nothing says September like a new uniform, preferably one you won't grow into for about three years. And I'm not talking about the children.
I went to a girls' school with a purposely hideous uniform, designed presumably to make sure none of us would get pregnant before finishing our Alevels. If you were uber-cool (I wasn't) you shortened it and tightened it until you got sent home. If you were only ordinarily cool (I wasn't) you mutinously wore it long in school and rolled it over four inches at the waist to saunter home. Either way, one glance at someone's skirt and one at their tie (worn with fat knot, uncool: skinny side out, cool) revealed everything.
Sixth form was a long time ago. But if you think you're not still wearing a 'uniform' - and that others don't judge you on it - you're probably very wrong.
As this piece from science writer Ben Goldacre in the Guardian sets out, how women look can completely change people's perception of what they actually do: he cites a study showing female musicians were judged less proficient when they played in jeans than when they did so in a concert frock (even though the 'performance' was actually an identical tape recording, so musically there was no difference). If you don't look the part, you don't sound it.
Of course men are subject to similar judgements: would you trust a consultant in a scruffy Tshirt, or a white coat? But the big problem for women is managing careers where the 'right' uniform is really a man's: where you stand out like a sore thumb whatever you wear, because simply by being female you're not the norm. The strange obsession with what women politicians wear - from Jacqui Smith's cleavage to Theresa May's kitten heels - is partly because they can't wear what most people still think of as a politician's uniform, namely sober male tailoring: they stand out, no matter what.
My own uniform when I started covering politics was the dullest suit I could find: I was a young looking 26, constantly being mistaken for the secretary or the work experience girl, and desperately needed to look older. The big surprise was finding out years later that motherhood has an equally complicated sartorial code, where a brand of leggings or a Boden ballet pump can classify you as accurately as an old school skirt.
One of the reasons I've bought hardly any clothes for the last year is that I'm not sure what the dress code is for this particular stage of my life. Will I ever need a wardrobe full of suits again? If there's one thing more complicated than having uniform rules, it's not having any.